The missile was fired from Sukchon in South Phyongan province at around 3.31pm KST, the South Korea’s Joint Chiefs of Staff (JCS) said, according to a report by Seoul-based NKNews.
Japan’s coast guard said that the projectile fired by North Korea has likely landed outside the country’s exclusive economic zone.
The missile appeared to have fallen into the sea minutes after the launch was first reported, the coast guard said.
The Republic of Korea and the US are “closely coordinating to maintain a full readiness posture”, the JCS said.
It is not immediately clear how far the missile flew. South Korea and Japan have not shared the range and more details about the projectile.
The post-noon missile launch triggered an alert from Japan’s coast guard, defence ministry, and the prime minister’s office which asked all units to prepare for contingencies.
The launch of the ballistic weapon comes just three days after North Korea fired four short-range ballistic missiles into the eastern waters on Saturday morning. Last week, North Korea fired at least 33 missiles towards the eastern waters.
These missiles reportedly flew about 80 miles, reaching 12 miles high before landing in the western sea, South Korea’s Joint Chief of Staff said.
The Kim Jong-un administration has fired a record number of missiles this year, stoking fears that North Korea is building up towards a seventh major nuclear weapons test.
This comes just a day after South Korea said it had identified debris from North Korea’s previous launch as part of Soviet-era SA-5 surface-to-air missile.
Seoul had previously said that the debris was initially part of North Korea’s short-range ballistic missile that landed near South Korea’s waters last week in a historic provocation.
Officials in Pyongyang had called the record number of missiles fired a response to “provocations” by the US and South Korea’s vigilant storm air drills that ran for six days till Saturday.
South Korea is currently participating in Taeguk Exercises — a unilateral computer-simulated combined post exercises (CPX) — which will be wrapped up on Thursday.